: In a patient with massive ascites, bouts of fever of unknown aetiology and cachexia, duodenoscopy and laparoscopy revealed white-yellow, partly confluent, nodules and plaques on the duodenal mucosa, and the surface of the liver and the peritoneum of the upper right abdominal quadrant, leading to the diagnosis of Whipple's disease. Histological examinations of these deposits revealed an accumulation of PAS-positive macrophages (SPC cells = sickle-form particle containing cells) and lysosomal bacterial inclusions under the electron-microscope. This raises the possibility of a simple endoscopic method for diagnosing Whipple's disease.